Pneumatic doffing mechanism for cotton gins and the like



A. L. VANDERGRIFF PNEUMATIC DOFFING MECHANISM FOR COTTON GINS AND THE LIKE March 11, 1952 2 SHEETS-SHEET 1 Filed July 5, 1948 Zinventor 1 70 54 Z. VIA/0525.61,?

(Ittomegs March 11, 1952 VANDERGRIFF 2,588,593

PNEUMATIC DOFFING MECHANISM FOR COTTON GINS AND THE LIKE Filed July 5, 1948 2 SHEETS-SHEET 2 3nventor flew-:1. A. Vwvoseaelrf Patented Mar. 11, 1952 UNITED STATE PNEUMATIC DOFFING MECHANISM FOR COTTON GINS AND THE LIKE Arvel L. Vandergriif, Columbus, Ga., assignor to Company, a corporation Lummus Cotton Gin of Georgia Application July 3, 1948, Serial No. 36,935

8 Claims.

My present invention relates to mechanism for dofling lint from the saws of a cotton gin or the like, and relates more particularly to mechanism for removing the lint by means of moving streams of air under pressure.

In the art to which my invention relates, lint The lint thus removed has been directed into the mouth of a lint duct, opening below the air blast nozzle. It has heretofore been considered that a large volume of air must be forced through accordingly with the advent of present day high speed gins, this large volume of air has necessitated increasing the size of air supply pipes, con- .10 of, and directing air tangentially of the saws.

.1 5 the nozzle to effect doffmg of the lint, and

densers, and conduits for handling the doffed lint. Consequently, the power required to oper-"--' ate the pneumatic dofiing apparatus has heretofore represented a disproportionately high part of the total power required to operate the entire ginning system. Further, I have found that these large volumes of dofiing air prevent effecting moting and cleaning of lint while it is on the saw cylinder. My experiments have indicated that such large volumes of dofiing air which I call primary air, induce large volumes of air above the mouth of the lint duct which enter the lint duct along with the primary air. This induced air serves not only to increase the total volume of air in the lint duct and conduits, thus requiring still larger conduits and condensers,

but also draws into the lint duct quantities of T trash and motes thrown from the saws by centrifugal force. I have found that without this large volume of induced air, trash and motes thrown clear of the lint fall downwardly and may be discharged from the gin along with other trash removed from the cotton by conventional mechanism in the gin.

In view of the above, it is a prime object of my invention to provide apparatus of the character designated which shall be efiective to doff lint from the saws of a gin with a greatly reduced volume of primary air over what has heretofore been considered necessary, thereby to permit the use of smaller condensers and smaller air and lint conduits, and to reduce the power required to operate the ginning system.

It is another prime object of my invention to provide pneumatic dofling means for cotton gins in which the volume of induced air is greatly decreased over prior apparatus, whereby improved moting and cleaning of the lint is obtained by permitting undisturbed discharge of the motes and trash thrown from the saws by centrifugal force.

More specific objects of my invention are to provide apparatus of the character designated which shall be simple and economical of construction, and which maybe installed in existing gins without major changes in the sins.

Briefly, my invention comprises a wall extending upwardly to lie closely to the peripheries of the individual, spaced saws forming the saw cylinder. On the surface of the wall adjacent the saws, I provide a plurality of spacers disposed to fit between the saws, and between which project a relatively narrow segment of the periphery of the saws. At the upper end of the spacers, I provide means for blowing individual streams of air under pressure between the spacers, tangentially onto the peripheries of the saws. The saws thus operate in individual, channel-like air passages, and each saw is doffed by an individual stream of air.

Spaced from the .first mentioned wall is a second wall, terminating below the saws. The two walls cooperate to form an open-ended lint duct. I provide continuations of the spacers which increase gradually in depth from the point of dofilng downwardly to a point approximately on a horizontal plane passing across the upper edge of the second wall. I preferably curve the first wall and spacers whereby they slope away from the saws immediately below the point of dofiing, and then turn back again toward the saws. I have found that this construction materially aids the discharge of lint, and assures that the lint is directed into the lint duct without also drawing thereinto motes and trash thrown by centrifugal force from the saws outwardly thereof over the mouth of the lint duct.

Apparatus illustrating the features of my invention is shown in the accompanying drawings forming a part of this application in which:

Fig. l is a detail transverse section through a cotton gin having my improved lint doffing mechanism associated therewith;

Fig. 2 is a somewhat diagrammatic fragmental perspective view illustrating the relation of the saw cylinder and my improved dofiing mechanism;

Fig. 3 is a fragmental front elevational view of the rear wall of the lint duct on which are mounted my improved spacers;

Fig. 4 is a front elevational view of one of the individual spacers removed from the gin;

Fig. 5 is a side elevational view of the spacer shown in Fig. 4; and,

Fig. 6 is a detail sectional view taken along line VIVI of Fig. 4.

Referring now to the drawings for a better understanding of my invention, I show my improved doffing mechanism associated with a gin embodying the usual rotating saw cylinder I9 comprising individual saws li, held axially spaced apart on a shaft H by means of the usual collars IS. The saws operate between huller ribs l4 and'ginning ribs l6. Seed cotton to be ginned is fed into the breast II of the gin from a slide l8, and falls downwardly to be acted upon by the picker rolls l9 and 2| which present the same to the saw cylinder H]. In the manner understood, the saws of the saw cylinder engage the seed cotton, and pull the same through the huller ribs l4 into the roll box 20. Hulls removed from the cotton fall downwardly through a perforated plate 22, and are discharged by means of a conveyor 23, which may be located below the floor 24 of the gin house. Seeds from which the lint has been removed fall downwardly between the ribs of the gin and are discharged through a seed conveyor 26. The gin may be provided with an overhead mote conveyor in the form of a fiat belt 25 on which motes and trash thrown from the top of the saw cylinder are removed. The gin may also be provided with the usual mote board 2'! onto which fall motes and trash thrown off by centrifugal force from the lower surface of the saws, such trash and motes sliding down the plate 2'! and being discharged along with the hulls by the conveyor 23.

On the rear side of the gin is an air chamber 28 extending substantially the length of the saw cylinder. The chamber 28 is supplied with air under pressure, as from a conduit 29.

The edge of the top plate 3| forming the air chamber 28 is bentdownwardly at 32. The sloping side 33 of the air chamber 28 is provided with a horizontal portion 34 spaced below the lower end of the downturned portion 32 of the top wall. The two edges thus cooperate to form an air nozzle 36 extending the length of the saw cylinder. The air nozzle is disposed to direct air downwardly and substantially tangentially of the saws to remove lint therefrom in the manner to be explained.

To receive lint after the same is doifed from the saws, I provide a lint duct '31 which comprises a curved front wall 38 and a rear wall 39. The upper edge of the rear wall 39 is provided with a horizontal lip 4| disposed to overly the horizontal portion 34 of the sloping wall 33 of the air chamber. Commencing at the air nozzle, the rear Wall 39 slopes downwardly and toward the saw cylinder to a point 42, and thence curves downwardly and away from the saw cylinder to a point 43. At point 43 the rear wall again turns back slightly toward the saws and is continued downwardly and then commences the regular curve toward the rear of the gin.

Secured by studs and screws to the rear wall 39 adjacent the air nozzle and on the side thereof toward the saw cylinder are a plurality of spacers indicated generally by the numeral 46. As shown in the drawing, the sides of the spacers fitting against the wall 39 follow the curved contour thereof. The upper ends of the spacers are relatively shallow and the surfaces of the spacers adjacent the saw cylinder follow the contour of the rear wall down to a point 41 below the upper end of the spacers. At point 41 the front surfaces of the spacers slope outwardly toward the saws and thence curve away from the saws, thereby to define a relatively deep lower end on each of the spacers. As shown more particularly in Figs. 4 and 6, the spacers preferably are wedge shaped on the lower ends as viewed in front elevation, and the front corners of the lower part are rounded. The upper shallow ends of the spacers project into the air nozzle and the upper edge 32 of the nozzle rests on top of each spacer. The spacers thus serve to divide the nozzle effectively into a plurality of individual nozzles each of which has leading therefrom a channel shaped air passage C.

The wall 38 is spaced forwardly of the rear wall 39 and its upper edge 48 terminates below the saw cylinder. The two walls 38 and 39 cooperate to define a lint duct with its mouth disposed to receive lint dofied from the saws. I preferably extend the deeper, lower ends of the spacers downwardly slightly below a horizontal plane passing across the upper edge 48 of the wall 38.

The saw cylinder I0 is mounted for rotation with each of the individual saws H thereof disposed in one of the channel-like passages defined between the spacers. Due to the curvature of the upper end of the spacers, only a small segment of the periphery of each saw projects at any one time below the front surface of the spacers. The

.lint on the saws is doffed at this point, indicated in the drawing by the numeral 50.

From the foregoing the method of constructing and operating my improved dofling mechanism may now be readily explained and understood. With the saws removing lint from the roll box 20, air under pressure supplied to the chamber 28 is forced from the nozzle 36 through the passages C defined between the spacers 46. Due to the curvature of the spacers at the point 50 and the curvature of the upper end of the rear wall 39, individual streams of air are directed downwardly and peripherially of the individual saws. Lint thus is dofied from the saws and is carried downwardly into the lint duct 37.

It will be especially noted that the spacers serve to take up the space between individual saws of the saw cylinder at the point of dofling. Therefore, instead of having to supply a volume of air great enough to fill these spaces between the saws, I am enabled to effect complete doffing of the saws with a greatly reduced volume of air. Consequently, with a lower volume of primary or doffing air the volume of induced air drawn into the lint duct over the upper edge of the front wall 38 is likewise considerably reduced. I have found that a certain amount of induced air is necessary to cause the lint to follow the contour of the wall 39 thereby to be delivered into the lint duct. I have found that with a small volume of induced air moving into the duct, motes and trash thrown over and floating in the air above the open mouth of the duct will not be drawn back \into the duct to the same extent as if a large air blast nozzle has heretofore been approximately 12 to 16 square inches. With my improved apparatus, I have reduced this area to approximately square inches for an 80 saw gin. As stated, this is brought about by extending the spacers into the air nozzle itself whereby they take up a considerable portion of the yolume thereof. Consequently, for an 80 saw gin, I am enabled to reduce the volume of primary air from 40 to 60 per cent over that required when using a conventional nozzle.

I have further found that the lint is caused to follow more nearly the contour of the wall 39 adjacent its upper end and hence be effectively delivered into the duct 31 by the provision of the lower extending ends on the spacers. My experience in operating gins embodying my invention indicates that these continuations of the spacers serve to control and prevent disruption of the flow of lint in each of the channel-like spaces C therebetween. This feature in combination with the relatively narrow segmental dofiing area at the point 5!] results in a doffing mechanism in which no lint is lost by blowing off into the gin, and at the same time permits the trash and motes thrown out of the lint over the mouth of the lint duct to fall by gravity onto the mote board 21.

It is to be noted that the outer surfaces of the lower deeper end of the spacers lli are spaced from the inner surface of the wall 38. I have found that so spacing the lower ends of the spacers with respect to the wall 38 is desirable in that it improves the lint discharge and cleaning characteristics of the apparatus.

While the overhead moting belt is not an essential element in the combination of elements shown and described, its use in conjunction with my improved doiflng mechanism results in a gin having exceptionally high cleaning efficiency. The overhead mote belt removes a large portion of motes and trash thrown off at the top of the saw cylinder, and my improved dofling mechanism prevents that portion of foreign matter thrown off the bottom of the saw cylinder from remixing with the lint.

From the foregoing it will be apparent that I have devised an improved mechanism for doffing lint from the saws of cotton gins which is simple of construction and wholly efiective for its intended purpose. I am aware that it has heretofore been proposed to provide lint ducts having openings therein for receiving the individual saws of the saw cylinder. However, such devices have not met with success for the reason that effective cleaning of the cotton is not obtainable therewith because the motes and trash thrown from the saw cylinder by centrifugal force have no Way to escape, and are drawn or thrown into the lint duct and become mixed again with the lint. In my improved apparatus, however, the induced air moving into the duct is insufficient to draw such trash and motes into the duct, and yet is of a volume sufficient to cause all lint doffed from the saws to be delivered into the duct.

While I have shown my invention in but one form, it Will be obvious to those skilled in the art that it is not so limited, but is susceptible of various changes and modifications, without departing from the spirit thereof, and I desire, therefore, that only such limitations shall be placed thereupon as are specifically set forth in the appended claims.

What I claim is:

l. In a cotton gin embodying a rotating saw cylinder, a rear wall extending substantially the length of the saw cylinder and having an upper portion disposed closely to the periphery thereof, a plurality of spacers mounted on the inner surface cf the rear wall and disposed between the individual saws of the saw cylinder, a front wall having its upper end terminating below the saws, said walls cooperating to define a lint duct open along its upper end for receiving lint removed from th saws, and means to discharge air under pressure downwardly between said spacers and onto the saws to remove lint therefrom.

2. Apparatus as defined in claim 1 in which the spacers are provided with portions extending downwardly to a point below the upper edge of the front wall.

3. In a cotton gin embodying a rotating saw cylinder, a wall extending closely adjacent the periphery of the saws means on the wall adjacent the saw cylinder defining vertically extending individual channels opening toward the saws and receiving the peripheries of the saws, a second wall spaced from the first wall with its upper edge disposed beneath the saws, said wallscooperating todefine a lint duct open along its upper end, and means to direct air under pressure into the upper ends of the channels and downwardly against the saws to remove lint therefrom and carry the same into the duct.

4. In a cotton gin embodying a rotating saw cylinder, a lint duct comprising spaced front and rear walls, the rear wall extending above the upper end of the front wall and with its upper end lying closely adjacent the saw cylinder, a plurality of spacers carried on the upwardly extending portion of the rear wall and defining channels in which the peripheries of the saws operate, downwardly extending portions on the spacers forming continuations of the channels, said extending portions continuing slightly below the upper end of the front wall, and means to admit air under pressure into the upper ends of said channels to remove lint from the saws and carry it into the lint duct. Y

5. In a cotton gin embodying a rotating saw cylinder, front and rear walls spaced apart to define a lint duct, means to mount the saws for rotation with the peripheries thereof closely adjacent the rear wall. means on the rear wall defining a channel like opening for receiving the periphery of each saw, said channel like openings being of greater depth at the lower ends than at the upper ends, said deeper lower ends of said channels extending downwardly into the lint duct, and means to force air through the shallow upper ends of said channels to strike the saws tangentially thereby to remove lint therefrom.

6. In a cotton gin embodying a rotating saw cylinder comprising a plurality of axially spaced saws for separating lint cotton from seeds and mechanism for discharging from the gin motes and trash thrown 01f the top of the saw cylinder. the combination of a rear wall disposed closely adjacent the periphery of the saw cylinder, a front wall spaced from the rear wall and with its upper end terminating below the upper end of the rear wall, said walls cooperating to form a lint duct open at its upper end disposed to receive cotton dofied from the saws, means on the surface of the rear wall adjacent its upper end defining a plurality of channel shaped passages for receiving the peripheries of the saws, an air nozzle disposed to supply air under pressure downwardly through said passages and doif cotton from the saws, and means to discharge from the gin motes and trash thrown on the bottom of the saw cylinder.

, 7. In a cotton gin including a rotating saw cylinder having a multiplicity of axially spaced saws for separating lint cotton from seeds, a lint duct defined by front and rear walls and disposed to receive lint dofied from the saws, the upper end of said rear wall extending above the upper end ofthe front wall and lying closely to the periphcry of the saw cylinder, a spacer between each of the saws and disposed on the rear wall adiacent its upper end, each of said spacers being curved to project inwardly of only a relatively narrow peripheral segment of the associated saws, an air chamber having a slot in one side, the upper ends of the spacers projecting into the slot and dividing the same into a plurality of the saws, a second wall spaced from the lower portion of the first wall and with its upper edge terminating below the saw cylinder, means on the inner surface of the upper portion of the first named wall dividing the same into channelshaped passages equal substantially in number to the number of individual saws on the saw cylinder,the peripheries of the saws extending into said channel-shaped passages, and means to admit air under pressure into the upper ends of the passages thereby to remove lint from the saws and carry it downwardly between said walls.

ARVEL L. VANDERGRIFF.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 910,653 Epps Jan. 26, 1909 1,022,259 Phelps Apr. 2, 1912 1,086,204 Murray Feb. 3, 1914 1,136,969 Moore Apr. 27, 1915 1,448,022 'Wood Mar. 13, 1923 2,275,755 Grimes Mar. 10, 1942 

